Ernst Lehner was one of the paciest and most skilled outside rights of the mid-/late-1930s. His specialty was corner kicks; gaining a reputation for often trying (and succeeding) to convert them directly. In a 1937 World Cup qualifier against Estonia, with Germany one goal behind at half-time, Germany collected 18 corner kicks in the second half, two of which Lehner converted directly and two other corners of his were headed into the Estonian goal by Jupp Gauchel (Germany won 4-1). Lehner was considered to have been one of the best outside rights of the 1934 World Cup. Others touted him as "the best non-professional player in Europe" (professionalism was not allowed in Germany in the 1930s). He was one of the players selected to represent Western Europe against Central Europe in 1937.
In his 1978 book "Fussball", Helmut Schön, manager of the West German national team (1964–1978), characterised Lehner as follows:
"His way of playing as an outside forward was the way I always wanted outside forwards to play: always ready to take up the ball, to stretch the game from outline to outline, a great dribbler and two-footed shooter."